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Lesquereusia spiralis
Lesquereusia spiralis, with dark colored mucus surrounding the collar

Lesquereusia spiralis (Ehrenberg, 1840)

Diagnosis: test colorless, circular or ovoid with an asymmetrical neck, slightly flattened laterally and composed of numerous siliceous curved rods interspersed with a meshwork of organic cement. Organic cement matrix between the rods has a distinctive rosette-like pattern. Neck prominent, sharply turned to ones side. Aperture terminal, circular and bordered by siliceous rods.

Dimensions: Length of shell 89-120 µm, breadth of shell 86-109 µm.

Ecology: in Sphagnum and detritus, feeding on diatoms and green algae.

Remarks:D. modesta and D. spiralis are sometimes hard to distinguish from each other and I am not sure if both species are  really different species.

Reported as Lesquereusia spiralis, but Lesquereusia is an incorrect, though widely used, emendation of the original genus name.

I have often found Lesquereusia spiralis with a black violet area around the aperture (see specimen above). I have found this specimens abundant in Sphagnum pools at two locations west of the town of Hilversum (Netherlands): het Hol near Kortenhoef and a peat bog along the Bert Bospad in Loosdrecht. The specimens seem to be covered with a layer of mucus.

Lesquereusia spiralis
Lesquereusia modesta
Lesquereusia spiralis, and L. modesta, typical forms
Lesquereusia spiralis
Lesquereusia spiralis
L. spiralis, both specimens from the same location (pictures stacked from several photographs)
Lesquereusia
Lesquereusia spiralis (stacked image) with a test composed of mineral plates and long thin needles. Some needles are clearly radial spines from heliozoa (see the the detailed images)
Lesquereusia spiralis
Siliceous elements or rods formed by Lesquereusia spiralis
Lesquereusia spiralis
Siliceous elements or rods formed by Lesquereusia spiralis (Olympus 100X oil, NA 1.30)
Lesquereusia spiralis
Lesquereusia spiralis
Lesquereusia spiralis feeding on algae
Lesquereusia spiralis
L. spiralis detail of shell, het Hol – stacked
Lesquereusia spiralis
L. spiralis detail of shell, het Hol – stacked
Lesquereusia spiralis
L. spiralis detail of shell, mixture of idiosomes and xenosomes – het Hol – stacked
Lesquereusia spiralis
L. spiralis – from Nuuk, Greenland, stacked
Lesquereusia spiralis
L. spiralis – from Nuuk, Greenland, stacked
Lesquereusia spiralis
L. spiralis with more or less disc shaped elements – from Hessen, Germany, collected and photographed (stacked) by Hans Rothauscher
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